I feel your pain and have been there before.

Now I am using TKLBAM I dont fear this situation with the one exception of lots of data - ie a NAS server or huge repository. The upload speeds in australia top out at around 1Mb/s (Yeh bits!) for ADSL2+ and nearly none reach the max speed... that equates to a max daily backup of 6-10Gb.

When I was in this position I took my old HDD out and installed a new setup on a new system then mounted the old in the new. This works fine if you dont have a striping RAID (RAID 1 is ok as its just a mirror). I think there is a way to mount raided volumes but I have had no experience with it. There are a million tutorials for doing this and its quite easy to mount a single drive - HERE is just one from a google search.

Another instance It had turned out to be bad RAM but we ended up replacing all components with old ones purchased off ebay before we realised. It was fairly cheap at $120 to buy them bu there is the search to find the right parts to contend with.

Which brings me to my next point - use decent hardware where you can!

Ubuntu Server keeps track of the network cards. If you replace the nic, which you have done, you might need to modify the persistent rules so your system forgets the old nic.

I found some instructions for Ubuntu 9.x and think 10.04 is exactly the same.  Try this and see what happens

http://www.serenux.com/2009/11/howto-fix-a-missing-eth0-adapter-after-mo...

Firstly, the command is 'ifconfig' (an abreviation of 'interface configuration') - that'd be why 'iconfig' is command not found...

Next, there is a config file for TKL confconsole (although may not be available in TKL v2009.x? - if that's what you'r running), you'll find it at /etc/confconsole/confconsole.conf

By default it's contents should look something like this:

# set default network interface
#default_nic eth0

So assuming that your Realtek card is providing eth2 (which sounds likely although you could run 'ifconfig' to check). then you will want to uncomment (ie remove the '#') from the second line and change it to eth2, so it looks like this:

# set default network interface
default_nic eth2

Hopefully that should get you going. If not you can configure it manually - do a search over on the Ubuntu forums (TKL v2009.x & v11.x are based on Ubuntu 8.04 & 10.04 respectively).

Having said all that though, the fact that your Realtek is coming up as eth2 (rather than eth1) makes me wonder if TKL is perhaps seeing the onboard NIC (and setting it as eth1) but perhaps just loading the wrong drivers or something? If you want to troubleshoot the onboard NIC, then I'd again suggest that you search/post over on the Ubuntu forums. I'd obviously be much easier to do with networking though...

Although if you are still running TKL v2009.x then I'd be looking to do a clean install of TKL v11.3 and mount your existing drive (like Chris descibes above). I'd imagine that unless your onboard NIC is something particularly exotic (which would surprise me) then TKL v11.x should pick it up straight away. If not then you should still be able to get it running relatively easily.

If you go that route and want to try to save as much of your current config as possible, if you can get networking working then you could run a TKLBAM backup without all of your file. To do that, read the TKLBAM man in the docs and exclude the file storage dir (/srv by default IIRC). If you go that route I'd also exclude the /etc/.git folder too (the etckeeper backups - on an old TKL server of mine there was over 500MB of cruft in there).